Figure 7.  TAP-deficient RMA/S cells express levels of Qa1 that are barely detectable with the 4C2 mAb, even after incubation with Qdm peptide
	Peptide	Stained with
	0	Med
	Db	Med
	Qdm	Med
	0	anti-Qa1
	Db	anti-Qa1
	Qdm	anti-Qa1
	0	anti-Db
	Db	anti-Db
	Qdm	anti-Db
TAP-deficient RMA/S cells were stained with the anti-Qa1 mAb 4C2 following incubation overnight at
26o with medium, 100uM of a Db-binding peptide WHMHHNMDLL, or 100uMQdm peptide.
Conclusions
1.  In contrast to the situation for TAP-deficient T2Q cells [Figure 3], TAP-deficient RMA/S cells [like all
other normal or malignant murine cells examined] express levels of Qa1 that are barely detectable by
staining with the 4C2 mAb, with or without preincubation with the Qa1-binding peptide Qdm.
2.  Whereas these extremely low levels of Qdm are sufficient to protect normal cells from NK cell lysis
[Figure 1 and Figure 2] and to sensitize RMA/S cells to lysis by CTL [Figure 6], they are insufficient to
RMA/S [and other] tumour cells from lysis by NK cells due to the high levels of activatory signals
delivered by tumour cells.